Drones, Open-Source Tools, and Open Science for Participatory Land Administration in Namibia’s Informal Settlements

Namibia's rapid urbanization has led to an increase in informal settlements, with an estimated 40 % of the country's urban population living in these communities. These settlements are characterized by unregulated land occupation, limited access to municipal services, and a lack of tenure security. The prevalence of poor housing conditions in informal settlements contributes to prevailing cycles of poverty, social exclusion, and vulnerability to environmental hazards. In order to support socio-economic progress, existing research emphasizes the need for inclusive urban planning, secure land tenure, and infrastructural development. Despite community-driven efforts, such as negotiations for group land ownership, water management, and participatory informal settlement profiling and household mapping by organizations like the Shack Dwellers Federation of Namibia, various challenges that hinder sustainable improvements remain. At the municipal and national levels, these challenges include insufficient geospatial data for planning and cadastral purposes.

To address these issues, we rely on advancements in open-source geospatial software and the capabilities of commercial drones (Unmanned Aerial Vehicles, UAVs). Together, these advancements allow for removing barriers when generating high-resolution geospatial data products. UAVs offer high-resolution imagery with centimeter-level accuracy that can potentially be employed for cadastral purposes, and their deployment is faster and more cost-effective compared to conventional field surveying methods. At the same time, open-source software, specifically OpenDroneMap, allows for the generation of geospatial data products, such as orthophotos, digital elevation models, and textured 3D models from captured drone images without additional licensing costs.

In this study, we conducted drone flights over informal settlements in Okahandja, a town in central Namibia that has not yet been mapped by the municipality. We conducted the fieldwork in close collaboration with the municipality and the informal settlements' residents, and drone flights were enabled by financial support from the Humanitarian OpenStreetMap Team. Our team surveyed ground control point markers, visible in the drone imagery, using real-time kinematic positioning based on existing cadastral ground control points outside the informal settlements to improve georeferencing. As a result, we generated orthophotos and digital elevation models with centimeter-level georeferencing accuracy and an image resolution of 6 cm/px, which is sufficient for layout planning and cadastral applications. We shared the data products with the municipality of Okahandja, with technical support from the Namibia Housing Action Group, and published the orthophotos on the OpenAerialMap platform under a CC-BY 4.0 license to encourage broader use by stakeholders, such as researchers, local authorities, NGOs, and community organizations. As a result, the data generated supports the community-driven land formalization process.

Our work highlights the potential of combining UAVs, the availability of open-source geospatial tools, and open science principles to address critical challenges within Namibia's informal settlements. The procedure provides high-resolution data for the municipalities' planning and cadastral needs and supports participatory informal settlement upgrading efforts. By enabling community involvement through open science, we show how technological advancements and good scientific practice can enhance participatory decision-making in land administration - particularly where the scope for shaping outcomes by governance structures alone is limited.